Hydroxy naphthylmethyl-amino bis propionitrile and bis propionic acid



3,265,724 Patented August 9, 1966 United States Patent Office 3,265,724 HYDROXY NAPHTHYLMETHYL-AMINO BIS PRO- PIONITRILE AND 1518 PROPIONIC ACID Mitchell F. Zienty, Elkhart, Ind., assignor to Miles Laboratories, Inc., Elkhart, Ind., a corporation of Indiana No Drawing. Filed Dec. 13, 1961, Ser. No. 159,151 5 Claims. (Cl. 260--465) This invention relates to new compositions of matter and to a process for preparing the compositions. In particular, the invention concerns hydroxy naphthylmethylamino bis propionic acid derivatives as new compositions having utility as antioxidants in protecting edible fats and oils against oxidative deterioration.

It is well known that certain edible fats and oils, especially commercially prepared products, such as lard and corn oil, are deficient in natural antioxidants. Because of this deficiency such products are highly vulnerable to deterioration in the presence of oxygen or air and will become rancid during storage, as characterized by unpleasant odors and flavors and off-colors.

The present invention resides in the discovery that certain derivatives of hydroxy naphthylmethylamino bis propionic acids display exceptional antioxidative properties when incorporated into edible fats and fatty oils and products containing these compositions. Specifically, the novel inhibitors of this invention comprise l-hydroxy- 2-naphthylmethylamino-N-bis(propionitrile), Z-hydroxy- 1naphthylmethylamino-N-bis(propionitrile), and the corresponding acids derived therefrorn: l-hydroxy-Z-naphthylmethylaminoN-bis(propionic acid) and Z-hydroxy-lnaphthylmethylamino-N-bis(propionic acid).

The novel compositions of this inventionmay berepresented by the following general formu1ason CHz-CH2X OHr-CHi-X OHr--N cm-om-x on tion of l-hydroxy-2naphthylmethylamino-N-bis(propionitrile) and the acid derivative thereof, is representative of the overall reaction:

CHPN-(CIIr-CHPCN. A I KOH onhnqom-cnr-ooom, H 4- The 2 hydroxy-1naphthylmethylamino-N-bis(propionitrile) compound of this invention, and the corresponding acid derivative, are obtained via the same'procedure i1- lustrated above, by using p-naphthol in place of .a-naphthol.

Specific properties of the aforementioned compounds which make them particularly useful as antioxidants are non-toxicity, solubility in fats and oils and absence of undesirable odors, flavors and colors when incorporated into fatty substances to be protected.

In the practice .of this invention the novel compounds are used to stabilize lard, castor oil and corn oil, but other materials which may likewise be protected include butter, beef tallow, linseed oil, rape seed oil, olive oil, palm oil, coconut oil, peanut oil, and the like.

To effectively inhibit oxidative deterioration in these materials the hydroxynaphthylmethylamino-N-bis propionic nitriles and acids of this invention are admixed therewith in small amounts, for example, from about 0.025% up to about 1.0% ,by weight, with the preferred concentration being about 0.025% to about 0.1% by weight.

When tested by means of the Swift Stability Test, commonly referred to as the Active Oxygen Method (AOM), subject antioxidants were found to retard rancidity in fats and Oils for substantially longer'periods of time than butylated hydroxy toluene, a well known lard antioxidant. The Swift Stability Test, which is described by A. F. King et' al. in Oil and Soap Journal, vol. 10, pp. -109 (1933), consists in general 'of bubbling air through a sample of lard until rancidity develops, that is, until 20 mini-equivalents of hydrogen peroxide per kilogram of lard are produced.

Referring to the test data set out in the following table, the figures shown represent the" time required (AOM time in hours) 'for rancidity to develop in lard, corn oil and castor oil when stabilized with the novel compositions of this invention, as compared to stabilization with butylated hydroxy toluene.

TABLE 1 AOM Time in Hours Inhibitor Corn Oil Lard Castor Oil l-hydroxy-Z-naphthylmethylam inoN-bis (propionic acid) 2-hydroxy-1-naphthylmethylamino-N-bis (propionic acid) l-hydroxy-Z-na hthylmethylamlnmN-hls (proplon e 2 hydroxy-l-naphthylntethylaminoN-bis (propionitrile) Butylated hydroxy toluene q 3: on NI mm m i The following examples serve to illustrate, but not to limit, the procedures used in preparing the novel compositions of this invention:

Example I.--Preparatin of 1-hydr0xy-2-naphthylmethylamino-N-bis(propionitrile) Example II.-Preparati0n of Z-hydroxy-I-naphthy[methylamino-N-bis(propionitrile) 12.3 g. (0.1 mols) of ,8,,3-iminodipropionitrile were dissolved in 125 ml. of dioxane and 7.5 ml. of formalin were slowly added dropwise. The resulting mixture was stirred for 1 hour at room temperature. To this mixture were added 14.4 g. (0.1 mols) of fl-naphthol all at once, and the reaction mixture was heated under reflux for 3 hours. The solvent, dioxane, was stripped oif under reduced pressure, leaving an oily residue. To induce crystalli'zation the oily mixture was treated with ether. The crystalline product was collected by filtration, dissolved in hot ether and allowed to cool to room temperature. Upon cooling the individual crystals separated from the solution to give the final product as a white, amorphous powder. Yield 27 g. M.P. l00-101 C.

AnaIysis.Calcd for C1'1H17N3OI N, 15.05. Found: N, 14.84.

Example III.--Preperati0n of I-hydroxy-Z-nuphthylmethylamin0-N-bis(pr0pionic acid) 61.5 g. (0.5 mols) of fi,'-iminodipropionitrile were dissolved, with stirring, in 500 ml. of dioxane. 37.5 ml. of formalin were slowly added dropwise and stirring was continued for 2 hours at room temperature. 72.08 g. (0.5 mols) of a-naphthol were then added all at once and the reaction mixture was heated under reflux for 6 hours. The solvent, dioxane, was stripped oil? under reduced pressure, leaving an oily residue, which was allowed to cool to room temperature. After cooling, 300 ml. of aqueous potassium hydroxide (65.0 g. potassium hydroxide in water) were added to the oily mixture and it was refluxed for 1 hour, during which time a considerable,

N, 4.40. Found: N, 4.51.

The solvent, dioxane, was tripped otf under re- Exarn'ple I V.-Preparati0n 0f Z-hydroxy-I-naphtlzylmethylamino-N-bis(propionic acid) 31.7 g. (0.1 mols) of Z-hydroxy-l-naphthylmethylamino-N-bis(propionitrile) were placed in a 3-necked flask equipped with a stirrer and reflux condenser. To this compound were added ml. of aqueous potassium hydroxide (37.5 g. potassium hydroxide in water) and the reaction mixture was heated under reflux for 3 hours. During the reflux period the potassium salt of the compound began to precipitate from solution. After reflux, the solution wascooled to room temperature, acidified with glacial acetic acid and the crude acid which precipitated was collected by filtration. The precipitate was dried, dissolved in hot benzene, treated with activated charcoal and filtered. The filtrate was treated with petroleum ether until the first permanent opalescence was observed and then cooled to room temperature to precipitate the final product as a colorless powder, melting at 197- 198.5 C. Yield 28.5 g.

AnaIysis.-Calcd for C I-1 N0 1 N, 4.40. Found:

Following are examples illustrating utilization of the novel antioxidants of this invention in stabilizing various edible fats and oils against oxidative deterioration:

Example V 5 mg. of l-hydroxy-Z-naphthylmethylamno-N-bis(propionic acid) (0.025% by weight) were added to 20 g. of melted lard. 1

A commercially available rendered lard product was used, which had an uninhibited induction period of approximately 6 to 8 hours. As shown by the test data in Table 1, above, stabilization can be increased to approximately 102 hours using the inhibiting compound of this example.

Example VI 1 Example VII 5 mgjof Z-hydroxy-l-naphthylmethylamino-l\ -bis(propionic acid) (0.025% by weight) were added to 20 g. of corn oil.

The corn oil of this example was a commercial product having an uninhibited induction period of approximately 3 hours. The test data of Table 1, above, clearly shows that stabilization of corn oil is increased .to about 16 hours using the antioxidant composition of this example.

In summary, the present invention pertains to the preparation and application of novel naphthy-lmethylamino- N-bis propionic acid derivatives as highly useful oxidation inhibitors for edible fats and fatty oils. Subject compounds are admixed with edible fatty materials in small amounts, ranging from about 0.025% to about 1.0% by weight. The preferred antioxidant is l-hydroxy- Z-naphthylmethylamino-N-bis(propionic acid), comprising about 0.025% by weight of the fatty composition to be stabilized.

What is claimed is:

1. A compound selected from the group consisting of compounds of the formula-- I OH I CHr-CHa-X 5 and compounds of the formula CHr-QHrX OHr-CHr- 0H wherein X is a member of the group consisting of CN and COOH. 4

2. l-hydroxy 2 naphthylmethylamino-N-bis (propio nitrile.

3. 2-hydroxy 1 naphthylmethylamino-N-bis (propionitrile.

4. l hydroxy 2 naphthylmethyLamino-N bis (pnopionis add).

5. Z-hydmoxy 1 n0ph't'hy1methylaminio-N bis (propionic acid).

Reppe et a1 260-518 X Chamberlin et a1 260465 Sallmann 260-465 X Thompson 99-163 Thompson 99-163 Pfister 260-519 Schnitz et al 2605 19 LORRAINE A. WEINBERGER, Pr imary Examiner.

R. S. AULL, D. R. MAHANAND, L. A. THAXTON,

Assistant Examiners. 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS OF THE FORMULA- 